Flight control surfaces may be constructed using a lay-up method in which an aluminum or steel mold is created, a foam core or removable bladder is inserted into the mold, and manual labor is needed to heat the mold, take it apart, and clean it up for further use. Another option is to use injection molding, in which the control surface is constructed in two parts and assembled together. Injection molding may result in thicker, and heavier, parts.